<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
    <title>Document</title>
    <style>
        .one{
            width: 100px;
            height: 100px;
            background-color: aqua;
        }
        .two{
            width: 100px;
            height: 200px;
            background-color: hotpink;
        }
        .three{
            width: 200px;
            height: 200px;
            background-color: yellowgreen;
        }
    </style>
</head>

<body>
    <div id="app">
        <div class="box" :class="className"></div>
        <h3 :style="[style,style1]">天天💭</h3>
    </div>
    <script>
        const vm = new Vue({
            data(){
                return{
                  className:{
                    one:false,
                    two:false,
                    three:true
                  },
                  style:{color:"red"},
                  style1:{fontSize:"30px"}
                }
            }
        }).$mount("#app")
    </script>
</body>

</html>